RE: [RFC PATCH v2 4/5] scsi: ufs: L2P map management for HPB read

Daejun Park
2020-06-18T01:45:16Z

> +
> > +static struct ufshpb_map_ctx *ufshpb_get_map_ctx(struct ufshpb_lu *hpb)
> > +{
> > + struct ufshpb_map_ctx *mctx;
> > + int i, j;
> > +
> > + mctx = mempool_alloc(ufshpb_drv.ufshpb_mctx_pool, GFP_KERNEL);
> > + if (!mctx)
> > + return NULL;
> So you use ufshpb_host_map_kbytes as the min_nr in your mempool_create,
> But you know that you need max_lru_active_cnt x srgns_per_rgn such mapping context elements.
> So you are
> a) failing to provide the slab allocator an information that you already have, and
> b) selecting from a finite pool will assure that you'll never exceed max-active-regions,
> even if some corner case fails your logic.
It was intend to provide user-configurable pre-allocated memory to reduce
latency due to memory allocation. The value of ufshpb_host_map_kbytes can
be set to max_lru_active_cnt x srgns_per_rgn, if the user want to.

Thanks,
Daejun